johnnyu
starting to shine!
Member since January 2011
Posts: 27
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Post by johnnyu on Apr 11, 2011 19:38:04 GMT -5
I picked this up for $5 at the Spokane WA rock show. It was so covered in dirt I could only see a very tiny bit of red. The rock was sold as Onyx as an auction item. I took a chance, won the auction, and then took it home and hit the grinder/polisher. I'm not an expert, but I don't think this is onyx! To me it looks like a lace agate but I don't really know. What is this??? Thanks for the help! On a separate subject - did anyone else see the "skull" in the serpentine jade from my earlier post. It was pretty interesting but I didn't get any replies. To me - it was relatively clear once it was pointed out. Just wanted to know if others could see it or not. Johnny U
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Post by frane on Apr 11, 2011 19:46:17 GMT -5
Hi Johnny, I am certainly no expert but I would say it is some kind of a poppy rhyolite. The side shot really does look like an onyx though so maybe it is one bumped up next to the other. I will have to see what others say. There is a lace onyx but I have never seen it look like this...(now I am going to have to find your other post to check for the skull) Fran
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,466
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Post by Sabre52 on Apr 11, 2011 20:46:27 GMT -5
First one looks like Medfordite which is basically the common name for one of the Jurassic poppy jaspers out of Oregon. Similar forms come from the Jurassic Franciscan Formation cherts all up and down the west coast ranges. You don't say how hard the second example is . If fairly soft ( scratches with a knife blade) I'd say travertine ( calcite onyx). If hard, one of the lace type agates even though the color scheme looks a bit unusual.....Mel
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Post by johnjsgems on Apr 11, 2011 20:47:45 GMT -5
Where is Mel? He is the resident expert on poppy jaspers. By definition "onyx" is chalcedony with repeating patterns. Many travertines mimic onyx and are even called onyx but they are not.
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johnnyu
starting to shine!
Member since January 2011
Posts: 27
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Post by johnnyu on Apr 11, 2011 20:55:49 GMT -5
Just to clarify - this is all the same rock - just a bunch of angles. I made a saw cut on one side to help it stand up properly. The opposite side I polished along with the face. The two opposite sides I left completely rough - only cleaned with soap and brush.
Thanks for all the input so far - I guess it may be onyx. I look forward to hearing from others.
Johnny
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Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,466
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Post by Sabre52 on Apr 11, 2011 23:30:13 GMT -5
*L* OK now I get it. Since it's all the same rock it's definitely "not" a poppy type jasper or an orbicular rhyolite and the orbs you're seeing are just due to cuts across mammilary growths of the bands. The poppy and the rhyolite don't form with that kind of banding. So then it comes down to hardness to determine if it's agate or travertine but I've not seen either in that particular combination of color and pattern so you've got me stumped *L*.....Mel
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Post by tandl on Apr 12, 2011 8:56:50 GMT -5
I think it`s mayer onyx .
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rocpup
spending too much on rocks
Pink Limb Iris
Member since March 2011
Posts: 465
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Post by rocpup on Apr 12, 2011 14:35:23 GMT -5
I have some of the same material and it is Onyx. Easy scratches with a knife. I have had it for years and do not remember the name. Don
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johnnyu
starting to shine!
Member since January 2011
Posts: 27
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Post by johnnyu on Apr 12, 2011 23:51:15 GMT -5
I checked it out compared to Mayer Onyx on the web. Looks like an exact match to the "Grand Canyon" variety of Mayer's Onyx.
Thanks for all the comments! Appreciate everyone's input.
Johnny
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MikeS
fully equipped rock polisher
Member since January 2009
Posts: 1,081
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Post by MikeS on Apr 13, 2011 15:30:22 GMT -5
I'd go with onyx....
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